I'm looking at Thru-hiker.com's fabric choices for sale, and I'm confused about "silicone Impregnated and "Silicone Coated". There is "SpinnTex Pro .8oz Silicone Impregnated Ripstop" for sale, but I was reading Ryan Jordan's article that says

"Silicone impregnated fabrics must be distinguished from silicone-coated fabrics (commonly referred to as “silnylon”). Silicone-coated fabrics are not breathable and are used in applications where lightweight waterproofness is required, such as tarps and bivy sack floors. In contrast, silicone-impregnated fabrics include those for which their water resistance is achieved without a laminate or coating..." etc.

Silnylon is made for the parachute and hot air balloon markets and the standards for firsts are very high, including not having too much coating.

I have used Thru-Hiker's silnylon seconds for for a shelters for several years now. No problem. (and it does rain where I camp)

I think what Ryan is calling silicon impregnated is fabric woven from thread that is impregnated with silicon. The threads themselves won't absorb water. It makes a somewhat water resistant and somewhat breathable fabric.

Silnylon that Thru-Hiker and others sell is high quality nylon fabric that is then treated through and through with a silicon sealer of some sort. Fairly waterproof but not at all breathable.

I have not bought from Rockywoods ... have never felt the need to buy from other that Thru-Hiker except in the rare case where I needed a particular color he did not have.